Under Voltage
Pentair
Line Undervoltage Protection
IntelliFlo / IntelliPro VS or VSF display shows “Under Voltage” and pump will not start or runs erratically.
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Safety Warning
This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.
If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.
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Possible Causes
Supply voltage below 207 V on a 230 V system, Long undersized wire run causing voltage drop, Loose connections at breaker or pump, Overloaded electrical circuit
How to Fix / Troubleshooting
Safety first: De‑energize the circuit before tightening any connections.
- Step 1 – Measure voltage: Have an electrician measure voltage at the pump terminals while the pump is running or attempting to start. If it drops below the minimum specified on the nameplate, the drive will fault.
- Step 2 – Inspect wire size and length: Compare the installed wire gauge and run length to Pentair’s installation manual. Long runs may require larger gauge wire to limit voltage drop.
- Step 3 – Tighten and clean connections: With power OFF, tighten all terminal screws at the breaker, junction boxes, and pump. Look for corrosion or burnt insulation and repair as needed.
- Step 4 – Dedicated circuit: Ensure the pump is on a dedicated breaker and not sharing with high‑draw devices (heaters, air conditioners) that can cause voltage sag.
- Step 5 – Re‑test: After corrections, clear the fault by cycling power and attempt to run the pump again.
Note: Persistent undervoltage can overheat the drive and motor. Correct the electrical supply before continued operation.
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Repair Difficulty
Hard
4/5
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